For a PC there is no problem as long as you have not connected a external Microphone.
But in laptops Microphones are built into. I do not need and do not want a Microphone, which I have no control.
Remove would be best, but is sometimes very difficult, also void the warranty and can damage the laptop...
So IMHO is the the only way to prevent this in the future reliable, seems to me to patch the kernel.
The best would be if the alleged audio data from mic come in reality from /dev/random...
Is there already a patch for this?

To really disable it, remove the microphone plug. This is the only real solution.

On a Laptop it becomes more difficult of course .... I would unselect the Audio Card module for the Sound Card. To disable only the microphone, i guess you need a custom patch for your sound card module. I am not aware of any other method to permanently disable the mic.

A guess of a hack for ALSA: redefine devices to make default input read /dev/zero instead of a microphone?
I know, it's not perfect, but it might be a silencer good enough for most cases. You know, default input tends to be set to something sane
Also, calling hardware directly for playback prevents other applications from accessing it. Does it work for input as well? (redirect mike to /dev/null so it can't be used?)
Can't test it now as I don't have my PC around

seems this issue is finally getting resolved in a better way, looks like I'm going have to switch from chrome to chromium... (sadly, this phrase "trust us" holds no value anymore considering all these other issues like lenovo, and stuff...)

Yesterday, news broke that Google has been stealth downloading audio listeners onto every computer that runs Chrome, and transmits audio data back to Google. Effectively, this means that Google had taken itself the right to listen to every conversation in every room that runs Chrome somewhere, without any kind of consent from the people eavesdropped on. In official statements, Google shrugged off the practice with what amounts to “we can do that”.

It looked like just another bug report. "When I start Chromium, it downloads something." Followed by strange status information that notably included the lines "Microphone: Yes" and "Audio Capture Allowed: Yes".

I hope we don't have to get to the day we have to run on machines that "don't have sound cards"... meaning, a VM with either no sound or fake sound card that's always silent._________________Intel Core i7 2700K@ 4.1GHz/HD3000 graphics/8GB DDR3/180GB SSDWhat am I supposed watching?